fix(docs): add babel plugin for styled components (#1001)

### 🐛 Bug

Some styling is completely messed up. This is most visible in the SDK
landing page for some reason. But also there is a padding missing in the
docs hompage.
The reason for this is that classes generated by styled-components are
not being added correctly.

### 🛠️ Fix

It seems that
[CSS-in-JS](https://docusaurus.io/docs/styling-layout#css-in-js) is not
supported by Docusaurus natively. I don't know why until now it has
somehow worked and started breaking just now...
In any case, by adding a babel plugin it seems that the code is now
transpiled correctly and the final build works with styled-components as
it should.

Author: baldasseva

babel.config.js

@@ -1,3 +1,4 @@
 module.exports = {
     presets: [require.resolve('@docusaurus/core/lib/babel/preset')],
+    plugins: ['babel-plugin-styled-components'],
 };

package-lock.json

@@ -40,6 +40,7 @@
         "@types/react": "^18.2.8",
         "@typescript-eslint/eslint-plugin": "^7.0.0",
         "@typescript-eslint/parser": "^7.0.0",
+        "babel-plugin-styled-components": "^2.1.4",
         "cross-env": "^7.0.3",
         "eslint": "^8.46.0",
         "eslint-plugin-json": "^3.1.0",